An occupant monitoring device configured to monitor a physical condition of an occupant of a vehicle, based on a captured image may be installed in a vehicle compartment in order to prevent a vehicle accident or the like.
For example, in an occupant monitoring device disclosed in Japanese Patent Application Laid-Open No. 2004-78778, a face of a driver in a vehicle is continuously imaged by an imaging unit, and a predetermined area corresponding to the face in a captured image is set by an area setter. Images of the predetermined area are collected in time series, difference values of the images are calculated by a time difference value calculator, and a direction of the face is determined by a face direction determiner, based on the difference values. The imaging unit is configured of a camera or an image sensor (imaging element) such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) or the like. The area setter, the time difference value calculator, and the face direction determiner are provided in a controller such as a microcomputer or the like.
In addition, in an occupant monitoring device of Japanese Patent Application Laid-Open No. 2009-200718, an imager configured to image a driver seat direction is installed on a steering column of a vehicle, and a plurality of illuminators configured to project near-infrared light in the driver seat direction are embedded in a rim of the steering column. The imager is configured of a near infrared CCD camera, and the illuminators are each configured of an LED (light emitting diode). A controller such as a driver monitor ECU (electronic controller) or the like controls operation of the imager and the illuminators, and processes an image captured by the imager, and detects a direction of a face of a driver and an opening/closing degree of eyes to output a detection result to a driver support system ECU.
An imager is contained in a housing (frame) as disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 10-254053. In Japanese Patent Application Laid-Open No. Hei 10-254053, a window is provided in the housing in order to allow external light to enter the imager. The window is configured of a plate-like member having a light transmission property, and is fitted in a through hole formed in the housing. An interior of the housing is waterproofed by arranging the plurality of windows in parallel or sandwiching an O-ring between each of the windows and the housing.